That question was on the minds of many in the state and elsewhere along the West Coast after a tsunami warning (and a minor tsunami) was triggered by a magnitude-7.9 earthquake that struck more than 170 miles off the coast of southeast Alaska, just after midnight on Tuesday.

Tsunami warnings were issued for parts of Alaska and Canada, while watches were issued in Washington, Oregon and California.

All were canceled within a few hours, and no damage was reported, but alerts sent to cell phones and calls for evacuation in some areas were enough to send people to social media asking whether California could really be hit with a dangerous tsunami. It didn’t happen this time, but we looked to the past for other examples.

Here are some answers to questions you night have about tsunamis in California.

What exactly is a tsunami?

A tsunami, according to the National Oceanic and Atmospheric Association, is a series of large waves generated by an undersea disturbance near the coast or in the ocean. The waves, which can travel across oceans, can be extremely dangerous and damaging when they reach the shore. Tsunamis can be caused by earthquakes, volcanic eruptions, underwater landslides and even unusual events such as meteorite crashes.

Has California experienced dangerous tsunamis before?

Yes. Here are the biggest ones in the last century, with some details of what happened each time.

1946: In April of 1946, a magnitude-8.6 earthquake that occurred near the Aleutian Islands (southwest of Alaska) led to a tsunami that affected Alaska, Hawaii and much of the West Coast. In Hawaii, the waves reached about 55 feet high and killed 158 people, most in the town of Hilo.

In California, the highest waves were more than 8 feet and killed one person in Santa Cruz. The Half Moon Bay area saw an estimated $20,000 worth of damage to boats and structures along the waterfront.

1964: Another Alaskan earthquake — this time a magnitude-9.2 quake that occurred in the Prince William Sound region — wreaked havoc in California in 1964, especially in Crescent City, where it killed 12 people and caused an estimated $15 million in damage. The number of deaths from the earthquake totaled 131 with 115 in Alaska and 16 in Oregon and California.

2011: A magnitude-9.0 earthquake near the coast of Honshu, Japan, triggered a tsunami in 2011 that not only devastated Japan but also traveled all the way to California. The resulting waves of at least 8 feet led to one death and an estimated $39 million worth of damage to the harbors of San Luis Obispo, Santa Cruz, San Mateo, Del Norte, Mendocino and Humboldt counties.

What are the chances a major tsunami hits California?

Major tsunamis occur in the Pacific Ocean region only about once per decade, according to the National Oceanic and Atmospheric Association, and only a few have brought many major impacts to California.

Some of the latest research about the risk to California includes a study in 2015 published by University of California, Riverside and the U.S. Geological Survey that found that the Ventura area especially is at greater risk for a tsunami than previously believed because of the faults deep beneath the Santa Barbara and Ventura areas. The study was based on a hypothetical 7.7-magnitude earthquake that could bring waves 20 feet high to Ventura Harbor and the Channel Islands Beach area.

How should California residents prepare for a tsunami?

After the earthquake on Tuesday, the Federal Emergency Management Agency (FEMA) and other emergency response organizations sent out reminders for people in threatened areas to refresh their tsunami-preparedness.

Advice from FEMA includes keeping an emergency kit handy and knowing your community's warning systems and disaster plans, including evacuation routes. Read the agency’s full list of tsunami guidelines here.